Xiidra has been on the US market since summer of 2016. Shire filed for approval in Europe just over a year ago, and I have not seen any news about the approval process since then.

Anyway, this study, which is a large one (2464 participants spanning 5 different trials) is about safety and tolerability (as opposed to, does it work?)

Overall, the results look relatively positive to me, relativity meaning in the context of 15 years of hearing constant complaints about persistent burning with Restasis!

The biggest problems are eye irritation and bad taste, both at about 15%. The noteworthy take-home for me (echoing what I've been hearing/reading from users since Xiidra came out) is that side effects are pretty short-lived... this study says comfort improved within 3 minutes of instillation and that itself improved over time. Anyway, we'll see, and I hope it gets approved in Europe soon. - Mind, the question of how well it's WORKING and for whom is obviously of much more interest to most of us.

Eur J Ophthalmol. 2018 Aug 16:1120672118791936. doi: 10.1177/1120672118791936. [Epub ahead of print]

Safety and tolerability of lifitegrast ophthalmic solution 5.0%: Pooled analysis of five randomized controlled trials in dry eye disease.
Nichols KK, Donnenfeld ED, Karpecki PM, Hovanesian JA, Raychaudhuri A, Shojaei A, Zhang S.

Abstract
PURPOSE:
Characterize the safety and tolerability of lifitegrast ophthalmic solution 5.0% for the treatment of dry eye disease.

METHODS:
Pooled data from five randomized controlled trials were analyzed. Key inclusion criteria were adults with dry eye disease (Schirmer tear test score ⩾1 and ⩽10 mm, eye dryness score ⩾40 (visual analog scale 0-100), corneal staining score ⩾2.0 (0-4 scale)). Participants were randomized to lifitegrast ophthalmic solution 5.0% or placebo twice daily for 84 or 360 days. Treatment-emergent adverse events and drop comfort scores were assessed.

RESULTS:
Overall, 2464 participants (lifitegrast, n = 1287; placebo, n = 1177) were included. Ocular treatment-emergent adverse events occurring in >5% in either group were instillation site irritation (lifitegrast, 15.2%; placebo, 2.8%), instillation site reaction (lifitegrast, 12.3%; placebo, 2.3%), and instillation site pain (lifitegrast, 9.8%; placebo, 2.1%); the most common (> 5%) nonocular treatment-emergent adverse event was dysgeusia (lifitegrast, 14.5%; placebo, 0.3%). The majority of treatment-emergent adverse events were mild to moderate in severity. Discontinuation due to treatment-emergent adverse events occurred in 7.0% (lifitegrast) versus 2.6% (placebo) of participants (ocular: 5.5% vs 1.5%; nonocular: 1.9% vs 1.1%). Drop comfort scores with lifitegrast improved within 3 min of instillation and the score at 3 min improved across visits (12-week trials (both eyes, day 84 vs 0): 2.0 vs 3.3; SONATA (day 360 vs 0): right eye, 1.2 vs 1.7; left eye, 1.2 vs 1.8).

CONCLUSION:
Lifitegrast ophthalmic solution 5.0% appeared to be safe and well tolerated for the treatment of dry eye disease. Drop comfort with lifitegrast improved within 3 min of instillation.